Mesa Verde.

“The farther backward you can look, the farther forward you are likely to see.” – Winston Churchill

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Mesa Verde Kiva

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Mesa Verde, Spanish for green table, offers a spectacular look into the lives of the Ancestral Pueblo people who made it their home for over 700 years, from A.D. 600 to A.D. 1300. Today, Mesa Verde National Park protects over 4,000 known archeological sites, including 600 cliff dwellings. These sites are some of the most notable and best preserved in the United States.

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Mesa Verde National Park is located in southwestern Colorado midway between Cortez and Mancos off US 160.

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Park Point

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View to the west of the north side of Mesa Verde, which looms high above the Montezuma Valley in southwest Colorado. The great Aztec ruler Moctezuma (whose name was later corrupted to Montezuma) never came this far north but early American settlers attributed the nearby ruins to his dynasty in Meso-America (Mexico). When the Anasazi (or Ancestral Puebloans if you like) lived here in the 13th century AD, there were over 40,000 inhabitants of the Montezuma Valley, more than twice the current population of Cortez, Colorado.

The north flank of the mesa is carved into south-dipping sediments that are of Cretaceous age. As rocks fall off of the edge of this escarpment, it retreats slowly through time to the south (towards the left in this view). That means that these layers once extended up slope farther to the north (to the right) and onto the southern flank of the San Juan dome, a Laramide-age uplift present in southwest Colorado. The rate of retreat on this escarpment can likely be figured out using rates from nearby areas on the Colorado Plateau and may be on the order of about one meter every 2,000 years.

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Mesa Verde North

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Beyond Mesa Verde to the west is the Sleeping Ute Mountain, a laccolith about 28 million years old.

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Mesa Verde sandstone

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The angled beds of sandstone here are likely point bar deposits from a stream meandering on a coastal plain, some 82 million years ago. As the Cretaceous Seaway retreated to the east, it exposed a low-lying plain that was coursed by many rivers. A map of Menefee time is provided two images down. The black layers are coal seams within the Menefee Formation.

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Spruce Tree House

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A view of Spruce Tree House in Mesa Verde National Park. The inhabitants used local blocks of the Cliff House Formation to construct these dwellings. The Cliff House represents deposition as the Cretaceous Seaway crept back over the Mesa Verde area about 80 million years ago.

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Square Tower House

Square Tower House always delights visitors with its four story tower and symmetric preservation. Note the desert tapestries that streak the inside walls of the alcove. These form wherever water preferentially drips from above, allowing for the growth of desert varnish.

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Cliff Palace

The largest cliff dwelling in the US is Cliff Palace with more than 250 rooms. It was an ideal location to build a small village as it receives much winter sun and summer shade. It is built within one of the larger and most well-developed alcoves in MVNP. The alcoves form within the Cliff House Formation, which consists of two massive sandstone bodies separated by a softer sandy shale. This alcove formed at the contact of the upper sandstone and the sandy shale horizon. It was here that groundwater pooled and dissolved the cement in the upper sandstone long before the canyons were cut. Upon exposure the weakened sandstone disintegrates progressively to form the alcove.

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Cliff Palace ruin

A close-up view of the heart of Cliff Palace ruin with a park ranger and lone visitor for scale on the far right. This is reportedly the very first ruin that was glimpsed by Richard Weatherill and Charlie Mason in December, 1888 and is what led to the discovery of this entire ruin complex.

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Manos and metates

Manos (hand-held grinding stones) and metates (grindiing surfaces) lay upon the “frozen” ripple marks of the Cretaceous shoreline. Certainly these people must have wondered about the lithified ripples that are so clearly exposed on the floor of Balcony House……..

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Balcony House

…..especially with such detail of preservation! These are exposed in another ruin site located on Long Mesa. They look as if a foot print today could be made in soft sand. The ripple marks are symmetrical meaning that they likely formed in the broad swath of tide zone, rather than on a river floodplain. The water in a tidal zone is bi-directional and the ripples then become symmetrical in cross-section. In a river, the water is uni-directional and the ripples are formed asymmetrically.

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“Mesa Verde is an archaeologists paradise but another fascinating aspect of a visit here lies in its geologic story. What geologic thinking provides us is a way to shift time scales instantaneously – such as when we see a 1,000 year old metate laying on top of 80 million year old ripple marks.” – Wayne Ranney

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Filed under American Southwest, Geology

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